-17.' 



MKTALLURGY. 





ottered bettor than the ordinal m;- 



now obtain*! by win* the ingredient* in a tittle 



dinVrrni proportion from llu*f UM-d in tin- HrM 



older, and ha* a peiwntaffp <xuii|M*ition--ftlu- 



miiium. frtt; * 



phoruA. OU4. This eolder ha* come largely into 



ttte in Oertnanv. Switzerland, Kngland. and the 



i 



icthod has been devised for imparting 

 hanlncM to aluminum by the addition of chn>- 

 miiiin. tare has to be taken in the process to 

 secure a true alloy, which i> diffloolt <n account 

 ..f i hr difference in the BMttinf joints of the 

 two metal*. The aluminum is said to be made 

 a* hard as steel by this moih<Hl. F. A Hard, of 

 Quebec, is credited with the discovery of a 

 method of tempering aluminum, so as to give it 

 the eon*i*t. ;. v ,,f iron. 



To cover aluminum with other metals, Ib-rr 

 Heesen. of llorlin. plunks it into caustic potash 

 or soda, or into bjdroohlork arid till bubbles 

 of gas appear: then into a rotation of OOlTOi?W 

 sublimate, by which an amalgam is produced on 

 the surface. The fir-; immersion is then re- 

 poatoil :<>> the ahuniniun is plunged 



into a fa salt of the metal of which a 



coating is desired. A closely adherent laver of 

 thin substance is rapidly formed. So perfect is 

 the adhesion of silver, gold, and copper that a 

 plate covered with either of these metals can be 

 hammered or polished. 



(..'Id. Concerning the relative cheapness of 

 the cyanide and the i-hlorination processes for 

 extracting gold, Mr. K. A. Schneider publishes 

 the conclusions, in the "Engineering and Min- 

 ,rnal."that under exceptionally favorable 

 ling is cheaper than chlorina- 

 tion, but under all circumstances it is safer to 

 operate chlorination works. Chlorination can 

 be successfully applied to almost any ore, while 

 cyaniding gives satisfactory results only with a 

 certain class of ores. The cyaniding process 

 labors under the disadvantage of requiring, in 

 most instances, an extremely skilled chemical 

 supervision. The chemical nart of the chlorina- 

 tion process is, on the other hand, very simple. 



In the llaycraft process of gold extraction 

 the ore is passed through a fine crusher and con- 

 veyed to an iron pan having a capacity of one 

 ton ore. Beneath the nan is a furnace. Water is 

 mixed with the ore to bring it to the consistency 

 of thick pea soup. A vertical shaft, having r. ; - 

 volving arms attached to keep the contents of 

 the pan constantly stirred, works in the cal- 

 dron. The arms are fitted with carbon shoes, 

 which form the anode through which the elec- 

 tric current passes through the saline liquor to 

 the bottom of the pan, which, with a dish ..f 

 quicksilver in the middle, forms the cathode. 

 Common salt or other chloride is added to the 

 water: the salt being decomposed by tin ! -trie. 

 current, the sodium passes to the mercury, and 

 the chlorine rising through the mass of pulp dis- 

 solves th* fine gold it meHs with and forms a 

 chloride of cold. As the pulp circulates in t he 

 pan this chloride comes under the operation of 

 the electric current and is decomposed in turn, 

 the ehlorine being liberated to seek more gold, 

 while the gold panes to the mercury cat hode. 

 thm producing amalgam. In the meantim 



panicles of gold that are too large to be 



dissolved by the chlorine gravitate to tl 



torn and are also inkeii hold of by the n. 



In the process of l>r. (ia/e. <>t 



which chloride of bromn 



solvent for gold, cau>iic soda is u-ed to 



the chlorine ami bromine, ami tin- _: 



. -red from the solution by !.< 



by chemical precipitant* ; at) import mil : 



the method employed for making tin- 



The process is a continual .-plittii. 



farming of the salts used. 



Me results in the perceir 



been obtained by 

 process, in which a mixt '. 

 nide and bromide is UN 



vent. It is indicated by some exp< 

 Mr. .1. 8, . Wells that n; 

 solvent i* more powerful than cyanidr 

 In a process by C. A. Mulholland, f r 

 i- used in nlace of cyanogen bromide. 



Mr. .1. .1. ChriMmas of Au-trab:. 

 have overcome the diili.-uliy of n-ing lea^^H 

 amalgamating metal and a means of obtj 

 gold from ores. In his method th- 

 tin- lead is prevented by passing the flnelj 

 on-, previously mixed'with a small inia- 

 kerosene or similar compound of 

 hydrogen, through a bath of the molten fl^H 

 The lead alloys with the gold and nlv : 

 the dry, pnwdered on-, being much light. 

 the lead, rises to the surface of t h.v 

 is carried away as tailings. In ti. 

 process the native ore, or sulphide of an 

 is melted in large crucibles, and when 

 point of cooling a quantity of molten 

 poured into the ore, stirred with an ; 

 poured into molds to cool. When the ii 

 turned out of the mold it is found that tl 

 which has a greater affinity for gold tl 

 antimony, robs the latter metal of il 

 tents, and, having a greater specific 

 ties to the bottom of the mold, from whi 

 easily removed and the gold recovered. 



Copper and Nickel. The ; 

 K. Lytle for producing hard copj- 

 now in use in Chicago, consists in ' 

 molten copper with a chemical (ompoun 

 ingredients are not disclosed, but which 

 ventor states is not an alloy, and i* int r 

 for its effect in rearranging the molecules of H 

 metal. Fractures of the treat ed 

 no indication of an alloy, but show ;< 

 acterist ics of pure copper. The castings ar 



' h and free from blowholes, i 

 specimens are shown of tough cas; 

 bars of the treated metal have been drawn 4 

 wire of high quality, and rolled cold itr 

 -t rips of great tenacity and perf 



By means of a new scleron 

 cate construction and exact action, i: 

 M. Paul Jannetaz, an interesting f 

 ing the relative hardness of /in< an-; 

 been brought to light. Most aut: 

 zinc as harder than copf.er. If. h- 

 metals are examined in a sufficiently pure stjj 

 copper appears to be the harder of th 

 removes an exception to the rulo tl 

 the body the less its atomic voi 



In its ordinary commercial form nickel, aide- 

 scribed by Mr. A. G. Charleton, conl 

 99 per cent, of metal, consisting of a spongeM 



